Spiral throat bushings are available from EnviroSeal Engineering Products Ltd. of Waverley, Nova Scotia, Canada under the SpiralTrac™ name. These patented devices (U.S. Pat. No. 5,553,868) have a spiral groove formed in a sloping face thereof and are generally positioned at the “bottom” of a seal cavity defined in part by a rotating shaft, a shaft housing, and a throat structure. The seal cavity typically, as well, may be filled with conventional packing or it may include a mechanical seal adjacent the end opposite the throat structure. These spiral bushings are intended to remove particulate material that may accumulate within the seal cavity during operation of the equipment, and may be augmented by flush fluids to help in material removal. The result of using these “internal” spiral throat bushings has been increased seal or packing life due to a significant reduction in wear.
Mechanical seals are designed to prevent leakage of process fluid to atmosphere, and are typically offered in a split or solid cartridge design. Typically, the seal is fastened to the face of the seal cavity housing by some mechanical means, such as threaded bolts or rods. The operation of the rotating equipment could be enhanced further if there was less particulate material entering the seal cavity from the vicinity of the mechanical seal.
Packing material is typically provided in annular rings and one or more such packing rings can be placed in a seal cavity and surrounding the rotating shaft. Again, operation of rotating equipment could be enhanced further if there were less particulate material entering the seal cavity past or from the vicinity of such packing material.